Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By checking out the USDA zone info for Johnston it's possible to determine when it's the best time to plant columbine.

Planting Calendar for Columbine

Frost tolerance for columbine:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant columbine just a bit earlier in the year because they are one of those plants that can tolerate a little bit of cold weather.

The earliest that you can plant columbine in Johnston is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant columbine and expect a good harvest is probably September. Any later than that and your columbine may not have a chance to grow to maturity. You can get started a little bit earlier by starting your columbine indoors.

Last Frost Date

In Johnston the average date of last frost happens on April 15. It might get as low as -20°F during the coldest months of winter.

Always keep in mind that USDA zone info for Johnston is not always accurate and the actual date of last frost is different every year. Half of the time in Johnston you get surprised by a frost after April 15 so make sure that you are prepared to protect your columbine if you have one of those late frosts.

USDA Zone Info for Johnston

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Johnston

You may be interested in your other planting guides for Johnston.